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Groups > linux.kernel > #1569971
| From | Mark Rutland <mark.rutland@arm.com> |
|---|---|
| Newsgroups | linux.kernel |
| Subject | Re: [PATCH v20 08/17] clocksource/drivers/arm_arch_timer: Rework counter frequency detection. |
| Date | 2017-01-30 19:00 +0100 |
| Message-ID | <t5opd-6Tg-43@gated-at.bofh.it> (permalink) |
| References | (1 earlier) <t0YD1-4Gk-45@gated-at.bofh.it> <t3d4S-79G-21@gated-at.bofh.it> <t3pz4-6Kn-17@gated-at.bofh.it> <t3zyr-4DC-45@gated-at.bofh.it> <t3L6x-3sr-13@gated-at.bofh.it> |
| Organization | linux.* mail to news gateway |
On Thu, Jan 26, 2017 at 01:49:03PM +0800, Fu Wei wrote:
> On 26 January 2017 at 01:25, Mark Rutland <mark.rutland@arm.com> wrote:
> > On Wed, Jan 25, 2017 at 02:46:12PM +0800, Fu Wei wrote:
> >> On 25 January 2017 at 01:24, Mark Rutland <mark.rutland@arm.com> wrote:
> >> > On Wed, Jan 18, 2017 at 09:25:32PM +0800, fu.wei@linaro.org wrote:
> >> >> From: Fu Wei <fu.wei@linaro.org>
> > For CNT{,EL0}BaseN.CNTFRQ, I am very concerned by the wording in the
> > current ARMv8 ARM ARM. This does not match my understanding, nor does it
> > match the description in the ARMv7 ARM. I believe this may be a
> > documentation error, and I'm chasing that up internally.
> >
> > Either the currently logic in the driver which attempts to read
> > CNT{,EL0}BaseN.CNTFRQ is flawed, or the description in the ARM ARM is
> > erroneous.
>
> Yes, those description did confuse me. :-(
>
> But according to another document(ARMv8-A Foundation Platform User
> Guide ARM DUI0677K),
> Table 3-2 ARMv8-A Foundation Platform memory map (continued)
>
> AP_REFCLK CNTBase0, Generic Timer 64KB S
> AP_REFCLK CNTBase1, Generic Timer 64KB S/NS
>
> Dose it means the timer frame 0 can be accessed in SECURE status only,
> and the timer frame 1 can be accessed in both status?
That does appear to be what it says.
I assume in this case CNTCTLBase.CNTSAR<0> is RES0.
> And because Linux kernel is running on Non-secure EL1, so should we
> skip "SECURE" timer in Linux?
I guess you mean by checking the GTx Common flags, to see if the timer
is secure? Yes, we must skip those.
Looking further at this, the ACPI spec is sorely lacking any statement
as to the configuration of CNTCTLBase.{CNTSAR,CNTTIDR,CNTACR}, so it's
not clear if we can access anything in a frame, even if it is listed as
being a non-secure timer.
I think we need a stronger statement here. Otherwise, we will encounter
problems. Linux currently assumes that CNTCTLBase.CNTACR<N> is
writeable, given a non-secure frame N. This is only the case if
CNTCTLBase.CNTSAR.NS<N> == 1.
Thanks,
Mark.
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[PATCH v20 00/17] acpi, clocksource: add GTDT driver and GTDT support in arm_arch_timer fu.wei@linaro.org - 2017-01-18 14:30 +0100
[PATCH v20 01/17] clocksource/drivers/arm_arch_timer: Improve printk relevant code fu.wei@linaro.org - 2017-01-18 14:30 +0100
[PATCH v20 02/17] clocksource/drivers/arm_arch_timer: Rename the timer type macros. fu.wei@linaro.org - 2017-01-18 14:30 +0100
[PATCH v20 06/17] clocksource/drivers/arm_arch_timer: rework PPI determination fu.wei@linaro.org - 2017-01-18 14:30 +0100
[PATCH v20 12/17] clocksource/drivers/arm_arch_timer: Refactor MMIO timer probing. fu.wei@linaro.org - 2017-01-18 14:40 +0100
[PATCH v20 16/17] clocksource/drivers/arm_arch_timer: Add GTDT support for memory-mapped timer fu.wei@linaro.org - 2017-01-18 14:40 +0100
Re: [PATCH v20 16/17] clocksource/drivers/arm_arch_timer: Add GTDT support for memory-mapped timer Hanjun Guo <hanjun.guo@linaro.org> - 2017-01-19 10:20 +0100
Re: [PATCH v20 16/17] clocksource/drivers/arm_arch_timer: Add GTDT support for memory-mapped timer Fu Wei <fu.wei@linaro.org> - 2017-01-19 11:10 +0100
Re: [PATCH v20 16/17] clocksource/drivers/arm_arch_timer: Add GTDT support for memory-mapped timer Hanjun Guo <hanjun.guo@linaro.org> - 2017-01-19 13:50 +0100
[PATCH v20 11/17] clocksource/drivers/arm_arch_timer: Introduce some new structs to prepare for GTDT fu.wei@linaro.org - 2017-01-18 14:40 +0100
Re: [PATCH v20 11/17] clocksource/drivers/arm_arch_timer: Introduce some new structs to prepare for GTDT Hanjun Guo <hanjun.guo@linaro.org> - 2017-01-19 09:30 +0100
Re: [PATCH v20 11/17] clocksource/drivers/arm_arch_timer: Introduce some new structs to prepare for GTDT Fu Wei <fu.wei@linaro.org> - 2017-01-19 11:00 +0100
[PATCH v20 07/17] clocksource/drivers/arm_arch_timer: Separate out device-tree code from arch_timer_detect_rate fu.wei@linaro.org - 2017-01-18 14:40 +0100
[PATCH v20 09/17] clocksource/drivers/arm_arch_timer: Refactor arch_timer_needs_probing fu.wei@linaro.org - 2017-01-18 14:40 +0100
[PATCH v20 13/17] acpi/arm64: Add GTDT table parse driver fu.wei@linaro.org - 2017-01-18 14:40 +0100
Re: [PATCH v20 13/17] acpi/arm64: Add GTDT table parse driver Hanjun Guo <hanjun.guo@linaro.org> - 2017-01-19 10:20 +0100
Re: [PATCH v20 13/17] acpi/arm64: Add GTDT table parse driver Fu Wei <fu.wei@linaro.org> - 2017-01-19 11:40 +0100
Re: [PATCH v20 13/17] acpi/arm64: Add GTDT table parse driver Mark Rutland <mark.rutland@arm.com> - 2017-01-19 12:20 +0100
Re: [PATCH v20 13/17] acpi/arm64: Add GTDT table parse driver Fu Wei <fu.wei@linaro.org> - 2017-01-19 13:30 +0100
[PATCH v20 05/17] clocksource/drivers/arm_arch_timer: Add a new enum for spi type fu.wei@linaro.org - 2017-01-18 14:40 +0100
[PATCH v20 08/17] clocksource/drivers/arm_arch_timer: Rework counter frequency detection. fu.wei@linaro.org - 2017-01-18 14:40 +0100
Re: [PATCH v20 08/17] clocksource/drivers/arm_arch_timer: Rework counter frequency detection. Hanjun Guo <hanjun.guo@linaro.org> - 2017-01-19 09:10 +0100
Re: [PATCH v20 08/17] clocksource/drivers/arm_arch_timer: Rework counter frequency detection. Fu Wei <fu.wei@linaro.org> - 2017-01-19 10:50 +0100
Re: [PATCH v20 08/17] clocksource/drivers/arm_arch_timer: Rework counter frequency detection. Hanjun Guo <hanjun.guo@linaro.org> - 2017-01-19 13:50 +0100
Re: [PATCH v20 08/17] clocksource/drivers/arm_arch_timer: Rework counter frequency detection. Mark Rutland <mark.rutland@arm.com> - 2017-01-24 18:30 +0100
Re: [PATCH v20 08/17] clocksource/drivers/arm_arch_timer: Rework counter frequency detection. Fu Wei <fu.wei@linaro.org> - 2017-01-25 07:50 +0100
Re: [PATCH v20 08/17] clocksource/drivers/arm_arch_timer: Rework counter frequency detection. Fu Wei <fu.wei@linaro.org> - 2017-01-25 08:30 +0100
Re: [PATCH v20 08/17] clocksource/drivers/arm_arch_timer: Rework counter frequency detection. Christopher Covington <cov@codeaurora.org> - 2017-01-25 16:40 +0100
Re: [PATCH v20 08/17] clocksource/drivers/arm_arch_timer: Rework counter frequency detection. Mark Rutland <mark.rutland@arm.com> - 2017-01-25 18:40 +0100
Re: [PATCH v20 08/17] clocksource/drivers/arm_arch_timer: Rework counter frequency detection. Fu Wei <fu.wei@linaro.org> - 2017-01-26 07:00 +0100
Re: [PATCH v20 08/17] clocksource/drivers/arm_arch_timer: Rework counter frequency detection. Mark Rutland <mark.rutland@arm.com> - 2017-01-25 18:30 +0100
Re: [PATCH v20 08/17] clocksource/drivers/arm_arch_timer: Rework counter frequency detection. Fu Wei <fu.wei@linaro.org> - 2017-01-26 06:50 +0100
Re: [PATCH v20 08/17] clocksource/drivers/arm_arch_timer: Rework counter frequency detection. Mark Rutland <mark.rutland@arm.com> - 2017-01-30 19:00 +0100
Re: [PATCH v20 08/17] clocksource/drivers/arm_arch_timer: Rework counter frequency detection. Mark Rutland <mark.rutland@arm.com> - 2017-01-31 12:50 +0100
Re: [PATCH v20 08/17] clocksource/drivers/arm_arch_timer: Rework counter frequency detection. Fu Wei <fu.wei@linaro.org> - 2017-01-31 19:50 +0100
Re: [PATCH v20 08/17] clocksource/drivers/arm_arch_timer: Rework counter frequency detection. Mark Rutland <mark.rutland@arm.com> - 2017-01-31 20:00 +0100
Re: [PATCH v20 08/17] clocksource/drivers/arm_arch_timer: Rework counter frequency detection. Fu Wei <fu.wei@linaro.org> - 2017-01-31 20:10 +0100
[PATCH v20 10/17] clocksource/drivers/arm_arch_timer: Move arch_timer_needs_of_probing into DT init call fu.wei@linaro.org - 2017-01-18 14:40 +0100
[PATCH v20 14/17] clocksource/drivers/arm_arch_timer: Simplify ACPI support code. fu.wei@linaro.org - 2017-01-18 14:40 +0100
[PATCH v20 15/17] acpi/arm64: Add memory-mapped timer support in GTDT driver fu.wei@linaro.org - 2017-01-18 14:40 +0100
[PATCH v20 17/17] acpi/arm64: Add SBSA Generic Watchdog support in GTDT driver fu.wei@linaro.org - 2017-01-18 14:50 +0100
Re: [PATCH v20 00/17] acpi, clocksource: add GTDT driver and GTDT support in arm_arch_timer Hanjun Guo <hanjun.guo@linaro.org> - 2017-01-19 10:30 +0100
Re: [PATCH v20 00/17] acpi, clocksource: add GTDT driver and GTDT support in arm_arch_timer Fu Wei <fu.wei@linaro.org> - 2017-01-19 12:20 +0100
Re: [PATCH v20 00/17] acpi, clocksource: add GTDT driver and GTDT support in arm_arch_timer Mark Rutland <mark.rutland@arm.com> - 2017-01-23 20:00 +0100
Re: [PATCH v20 00/17] acpi, clocksource: add GTDT driver and GTDT support in arm_arch_timer Fu Wei <fu.wei@linaro.org> - 2017-01-24 06:20 +0100
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